Characterization of a putative retroviral env-related human protein

In this study, we developed a rabbit polyclonal antibody to a fusion protein containing the envelope (env) transmembrane (TM) region from the human endogenous retroviral family, HERV-E. We used this reagent to document the expression of TM-related protein by Western blot in endothelial, colon and prostate carcinoma and seminoma cell lines and in peripheral blood mononuclear cells from a healthy donor. We detected a 58-kD protein (as compared to murine TM of 15 kD) that had specificity for the env-related antibodies of the polyclonal antiserum.